Near resonant charge transfer processes at thermal energies

Abstract

A useful procedure is described for the evaluation of near resonant charge transfer cross-sections at thermal energies. The method is based on a generalization of a semi-classical approach introduced by Bates and Mapleton for the study of symmetric resonant charge transfer processes. The rate coefficient is calculated for the reaction O++H⇆H++O as a function of temperature between 10 and 104 K; the results are compared to those obtained using the ‘orbiting approximation’. A brief application of these rates to the interstellar medium is made where it is found that substantial differences emerge between cases where the gas is heated by cosmic rays or by X-Rays.